The invention relates to a junction diode comprising different semiconductor materials or semiconductor alloys in different parts of the diode.
Some devices, as in Herner et al., U.S. patent application Ser. No. 10/326,470, “An Improved Method for Making High Density Nonvolatile Memory,” filed Dec. 19, 2002, hereinafter the '470 application, which is hereby incorporated by reference, employ a vertically oriented semiconductor junction diode. Dopant types and levels are varied throughout the diode, but the entire diode is formed of a single semiconductor or semiconductor alloy.
The present application pursues other ways to vary composition of a junction diode to improve device performance.